/* * This file is part of the libopencm3 project. * * Copyright (C) 2009 Uwe Hermann * Copyright (C) 2012 Karl Palsson * * This library is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library. If not, see . */ #include #include #include void clock_setup(void) { /* We are running on MSI after boot. */ /* Enable GPIOD clock for LED & USARTs. */ rcc_peripheral_enable_clock(&RCC_AHBENR, RCC_AHBENR_GPIOAEN); rcc_peripheral_enable_clock(&RCC_AHBENR, RCC_AHBENR_GPIOBEN); /* Enable clocks for USART2. */ rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_USART2EN); } void usart_setup(void) { /* Setup USART2 parameters. */ usart_set_baudrate(USART2, 38400); usart_set_databits(USART2, 8); usart_set_stopbits(USART2, USART_STOPBITS_1); usart_set_mode(USART2, USART_MODE_TX); usart_set_parity(USART2, USART_PARITY_NONE); usart_set_flow_control(USART2, USART_FLOWCONTROL_NONE); /* Finally enable the USART. */ usart_enable(USART2); } void gpio_setup(void) { /* Setup GPIO pin GPIO7 on GPIO port B for Green LED. */ gpio_mode_setup(GPIOB, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO7); /* Setup GPIO pins for USART2 transmit. */ gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO2); /* Setup USART2 TX pin as alternate function. */ gpio_set_af(GPIOA, GPIO_AF7, GPIO2); } int main(void) { int i, j = 0, c = 0; clock_setup(); gpio_setup(); usart_setup(); /* Blink the LED (PD12) on the board with every transmitted byte. */ while (1) { gpio_toggle(GPIOB, GPIO7); /* LED on/off */ usart_send_blocking(USART2, c + '0'); /* USART2: Send byte. */ c = (c == 9) ? 0 : c + 1; /* Increment c. */ if ((j++ % 80) == 0) { /* Newline after line full. */ usart_send_blocking(USART2, '\r'); usart_send_blocking(USART2, '\n'); } for (i = 0; i < 100000; i++) /* Wait a bit. */ __asm__("NOP"); } return 0; }